In a mixing bowl, add the mango cubes, salt and turmeric powder.Give it a mix and keep aside for 30 minutes.
After 30 minutes, drain out excess juices. Do not squeeze the mango cubes. Keep aside.
Heat oil in a pan.
Add the chillies (broken into large pieces), mustard seeds, fenugreek seeds, hing, cinnamon and saute for few seconds.
Add the mango cubes and saute for 5 minutes or so.
Add grated jaggery and keep stirring the mixture continuously on a low flame till the jaggery has dissolved and the mixture has turned thick and sticky.Cook only till the jaggery dissolves. Do not allow the jaggery to caramelize.
Turn off the heat and cool the mixture completely.
Add the chilli powder and mix well.
Transfer this mixture to a glass container or a jar.Keep aside for 5 days.
The pickle is ready to eat after 5 days.
Store this pickle in a cool, dry place. This sweet mango pickle can be stored for a long time ( 4 to 5 months).